Described herein is a method for creating surfaces to be utilized on rotating devices having rotational axes offset from being co-linear, and in a preferred form intersecting at a center location.
In general, the prior art related to rotary composite displacement devices has disclosed various types of mechanisms, some of which include mechanisms operating in a cyclic reciprocating-type pattern, such as a piston-and-cylinder type design which is utilized in most automotive engines. Other types of positive displacement devices, such as the Wankel engine, may have a reciprocating member which rotates with an elongated cylinder shaped somewhat like a peanut. The Wankel engine is of course a commercially successful engine utilized in various Mazda® automobiles.
However, one issue with the rotary devices as shown in the prior art is that the two mating gear-like members generally must engage one another or have a fluid film therebetween to maintain separation thereof. For example, as shown in U.S. Pat. No. 5,755,196 which is a patent assigned to the applicant's company, there is shown a device having two mating rotors, and follow-on continuation applications such as U.S. Pat. No. 6,739,852 by the same inventor show rotors having opposing engagement faces on either side of the lobe which engage a “pocket” region between two adjacent lobes on the opposing rotor. This type of device discloses a positive displacement device but, for example, if a low-viscosity fluid such as a gas is positioned within the bucket regions for a gas expander or a compressor, this low viscosity gas has difficulty maintaining a gap seal between the two rotors, and rotor-to-rotor contact can occur. The Klassen application U.S. Pat. No. 6,497,564 discloses an embodiment for balancing a slave rotor, thereby providing a prescribed gap on the slave rotor so that when a lobe is completely inserted into a bucket of an opposing rotor behind the casing seal of the surrounding casing as shown in FIG. 9 of Klassen, a fluid circuit path is provided to allow a balancing force on either side of the lobe so as to balance the slave rotor. This innovation was helpful for non-compressible fluids utilized as a pump or water turbine. However, with a gas the porting is substantially different in that a gas can be compressed. In, for example, an embodiment of a compressor, the ports are such that the contracting chambers of a rotary motion positive displacement device must reduce in volume before expelling the gas into an exit higher-pressure chamber.
Other prior art references, such as German patent 1,551,081 filed Jun. 6, 1967, show rotors constructed in a manner to have a lobe region and an opposing bucket region between two adjacent lobes of the opposing rotor. However, as shown therein, there are a plurality of small insert members, such as those shown in FIGS. 3 and 4 on the lobes, which provide sealing. As discussed in a best available translated English version of this disclosure, rollers and ball bearings are utilized to absorb the actual pressure movements. The disclosure of this particular German reference shows various types of spacing elements such as those shown in FIGS. 3 and 4 which are directly positioned on the lobes themselves.
Through various failures of rotary motion positive displacement devices, it became apparent that a need for positioning the rotors spaced apart from one another is required in certain operating environments. However, such a spacing system was not feasible because the rotors had to self-lubricate to maintain a fluid layer gap therebetween. Alternately, inserts such as that shown in the above-mentioned German 1,151,081 reference appear to be necessary to maintain a prescribed gap to mitigate wear between the rotors. Further attempts included having power sources on either rotor to apply torque thereto. In this form, if the device is utilized as (for example) a pump or a compressor, if equal amounts of torque are present on opposing rotors then there would be substantially less rotor to rotor contact. However, this requires that two torque-producing (e.g. motor) or receiving (e.g. generator) devices be placed on either opposing rotor.
As described in detail in the Klassen patent application U.S. Pat. No. 6,036,463, which is owned by the present applicant, it can be appreciated that in this application, as shown in the initial figures, there is a method of carving a rotor using a central axis that bifurcates the distance between the axis of rotation of the two opposing rotors. If one develops a cone around this axis and fixes the axis to one of the rotors, this cone will cut out a path in the opposing rotor. FIGS. 1-7C show this progression. Further, as described in U.S. Pat. No. 6,497,564, there is shown the full lobe design where the same process of forming the offset face is utilized on an adjacent portion of the rotor to make a lobe. As shown in U.S. Pat. No. 6,739,852 in FIGS. 15A-16B, the general process can be appreciated. The US patent references U.S. Pat. Nos. 5,755,196, 6,036,463, 6,497,564, 6,705,161, and 6,739,852 are all incorporated by reference in their entirety.
It should be noted that one issue with the embodiment as shown in the '196 patent was that there existed separation between the rotors, and not having a full lobe but rather only one-half of the lobe allowed the rotors to rotate apart from one another. Although creating a full lobe prevented such backlash, there is still the issue of rotor-to-rotor contact without some form of an indexing system.
Therefore, for a relatively considerable length of time it did not appear feasible to maintain an index position of two opposing rotors.
Disclosed herein is in one form is a novel method for having indexed rotors with a prescribed space whereby the operating lobes can maintain a prescribed rotational distance from one another during rotation and an indexing lobe positioned in one form at a longitudinally rearward portion of each lobe is utilized.